1. Technical Field
The present invention relates to automatic pleating machines and, more particularly, to a method and apparatus for forming apertures or holes in an accordion pleating machine. Although the end product produced by the method and apparatus has particular utilization in the fabrication of pleated lamp shades, other uses are certainly within the contemplation of the invention.
2. Discussion of the Prior Art
Automatic pleating machines employed in the prior art utilize a pusher bar in cooperation with a pleating or reefer bar to form a continuum of accordion pleats in a moving web of material. Such machines are manufactured and sold by: Mutual Manufacturing Company, Inc., of New York, N.Y. ("Rugged Accordion Pleating Machine"); Karl Rabofsky GmbH, of West Berlin, Germany ("RABO 88 Accordion Pleating Machine"); and Enguda Industrial Company, Ltd., of Taipei, Taiwan (Model C-67). Such machines are generally also described and illustrated in U.S. Pat. No. 2,677,993. Generally, in such machines, the pleating or reefer bar reciprocates along a path extending perpendicular to the moving web of material while the pusher bar reciprocates along a path extending generally parallel to the moving web, toward and away from the reciprocating pleating bar. The pleats are formed by compressing respective sections of the web material between the two bars during each reciprocation cycle of the bars.
For some pleated products, such as pleated lamp shades, it is necessary to provide holes or apertures in the pleats in order for a cord, wire or frame to be inserted through the apertures to properly contour the final lamp shade product. For example, such lamp shade products may be found in U.S. Pat. No. 2,122,971 (Angeletti), No. 1,570,230 (Chambers), and No. 2,714,155 (Johnson). It is conventional to form such holes or apertures with punches operated in synchronization with the motion of the web of material in order to provide spaced apertures along the length of the web. Spacing between the apertures is selected such that they are aligned in successive pleats formed downstream of the punch. Unfortunately, the apertures do not always register properly and considerable amounts of pleated material must be discarded. Reasons for the absence of registry include improper design or assembly, wearing of parts due to use, changes in synchronization control parameters, etc. Whatever the reason, improper registration of the apertures is wasteful and costly.